Simplistic NJFET RIAA

[Salas]

They look like good amps. I only had used Manley studio gear, and it was very good. Their vocal mic pre VoxBox was so much better than the Avalon. Only I had to repair it because it had fallen off a backstage rack. Just a phantom power switch damaged though. A worn out head amp valve too, but a new 12AX7LPS went in, and it rocked.

 

[RCruz]

My first listening impression using a sound card and a tube buffer before the amps is that they lack bass and have a too much trebble.... Maybe I will open a new thread on "how to mod a Manley"

 

[jonners]

Hello again!
I've just been tuning into this thread once more. It's been many pages since I last posted, so I don't know what I may have missed.
Anyway, I'm now using a DL-103 (Aluminium body) with a step-up transformer into the 40+dB version that I previously used with the DL-110. Sounds good to me, but I'm wondering if there's anything to be gained by eliminating the transformer and making the 60dB version?

 

[Salas]

A better transparency and a bit better SNR arguably, you eliminate much interconnect and winding wire, but it is a rather big effort and spare of resources if you already like the results and your transformer is notable and expensive. Tell me the turns ratio and termination resistor you use.

 

[jonners]

Hi Salas, thanks for your reply.
I'm using Altec 15095 line output transformers in reverse, so 150R:15k, but the loading I have on the output is less than 15K so the 103 is seeing around 100R.

 

[Salas]

Did you ever try to load the 103 with say 470R reflected impedance? Its the 40 Ohm coils standard one must I presume?

 

[jonners]

Yes it's the standard 103, but I've removed the plastic body and put it in an aluminium shell. (Worthwhile improvement).
I've tried higher loading, but found that I like 100R best (which I think is what Denon recommends?) - the lower impedance gives more body to the sound

 

[Salas]

They say 100R is minimum on their leaflet. Its true, the lower the load, the heavier they sound. With 40R source impedance we lose signal on 100R loading non the less. Maybe you have noticed that the output is stated always more than advertised, on the individually measured spec at 47k. But sometimes they tune carts on typical loads by judging their tone on such loads when they make them. 100R is a traditional load for MC. Give it that a system leans towards heavier or lighter tone, and everybody has a favorite load. Me I like it when I have balanced tone by not needing to load the cart less than 10:1 so I have all the signal, but if it needs to change so to balance out a system, then no worries. My 103R with 14R coils sounds just OK with 150R for instance in my system, and that is good for both considerations.

 

[Joao@AltheaMusica]

Hello Salas & Jonners

you've both the right opinions. My experience shows as well that step-up transformers and step-up amplifier stages are different in handling.

Please let me note that some audiophiles have the opinion to use the same load as the cartridge owns - here 40 ohms - which is in fact nothing more as the so called power matching. This was used in the past in radio stations and / or tone studios. I'd recommend to play with a potentiometer and find the best sonic value.

Maybe an additional stage with 20dB gain is the better solution when using a solid state phono stage.

 

[RCruz]

Two new 4 wire shunts ready for trial !!!

I could not set both for the same current due to differences in the leds.... One produces 260mA and the other 240... hope it does not affect the stereo presentation too much.

 

[Salas]

No problem. Same gfs region. Meeting the two regs CCS currents exactly does not tell you that you have matched anything else between them IRFPs anyway. Read some Pass articles about such matters. OTOH no worries here its not signal.

 

[disco]

Two new 4 wire shunts ready for trial !!!

I could not set both for the same current due to differences in the leds.... One produces 260mA and the other 240... hope it does not affect the stereo presentation too much.

Bravo. What cable did you use for the remote sensing wires?

 

[RCruz]

I am using 0,8mm multi strand silver cable... four in total.

Due to the actual layout it is not viable to use screened wire (The GND and +Vin in the Riaa boards are 5cm apart).

 

[disco]

I am using 0,8mm multi strand silver cable... four in total.

Due to the actual layout it is not viable to use screened wire (The GND and +Vin in the Riaa boards are 5cm apart).

* The ground can be extended without punishment for sheelding purpose.
* Some users reported gain from a thick (2mm diameter?) wire between regulator and phono board. If I remember correctly the argument was lowering output impedance. It might prove an acadamical exercise on 'not top of the bill' builds.

 

[RCruz]

It works very well !

On my initial listening tests I detect a lower noise floor with better detail retrieval.

Micro detail is enhanced so every sound is more inteligible.

I must wait until it settles and gets totally coherent

Ricardo

 

[psgr]

Salas,

Xpovia Polla

 

[Salas]

Cheers.

 

[merlin el mago]

Different questions

Hi Salas & everybody,

First of all sorry for the following a lot of of questions:

-I own a Denon DL-304, ultra low output voltage: 0.18mV & I want to do your Salas Simplistic NJFET Riaa but the schematics shown are for cartridges with more output voltage, I see your schematic for Denon DL-103 Stnd Gain 60dBs but I mind that I need more gain due to the fact that the 103 output is 0,3mV. Is possible changing the schematics get more gain? or I need to buy other cartridge with more output? because I disagree the set-ups

-I have several LSK389 on hand, is possible make the simplisitic with these other njfets? is necessary to change something or simply put half LSK389 instead each 2SK170?

-Due to the fact that I will do mine own PS, I need to know: how many VA for the transformer is needed (I suppose will be the same for all shunt regulators)& will is the voltage needed at the seconday depending each combination for the Universal Simplistic Phono Shunt Salas 2009.

-Where can buy with good price: matcheds for RIAA BC550C, & no matcheds for Shunt: BC546B, BC550C (I suppose the same like in "matcheds") & IRFP9140. For other shunts no matched: IRFP9240 or IRPF9620, IRFP240 or IRPF9620.

-For digital use: ic, clocks, oscillators etc. will be interesting to know how can do a shunt for 3.3V, is possible?

Thks in advance for your patience & kind advice

merlin el mago

 

[Salas]

Many questions indeed. Will reply later on when I can think. What kind of gain your preamplifier, amplifier have together, and what is the sensitivity of your speakers? That will help to answer.

 

[merlin el mago]

Thanks for you quick anwer, sorry to don't tell you before all the information needed about mine system, I am using:

-Balanced line preamp Erno Borbely with dual PS closed loop gain 20.8 dBs + 6 dBs balanced mode.
-Two mono power amp 75W RMS into 8 ohms Class A Erno Borbely
-Wilson Audio Cub 94 dBs 4 ohms

Now I am using like phono front end: cartridge Linn Arkiv / Denon DL-304 + Linn Linto + Ekos tonearm + LP12 + Lingo but I am not satisfied with the sound due to the fact that Arkiv first model specs are:

Stylus: vital
Tracking force: 1.55-1.75 g
Recommende load: more than 50 ohms
Weight: 7.4g
Separation 1 kHz: better than 30 dBs
Channel balance at 1 kHz: wthin 0.5 dB
Output at 5 cm/s at 1 kHz: 150uV

If you need the specs for Denon DL-304 (output 180uV) please be so kind to let me know.

I was planning to buy the Erno's phono with 73 dBs gain, because I suspect that the problem is the Linto phono amp that only have a gain of 66 dBs but like all Erno's line is a little bit high priced & in the same moment I read your interesting Salas simplistics njfet riaa & I take like a serious alternative

I know that are a lot of questions so I understand that you needs time to answer don't worry I am glad to wait.

Thanks again

merlin el mago